AbstractA mathematical model was developed for a percolation reactor in connection with consecutive first‐order reactions. The model was designed to simulated acid‐catalyzed cellulose or hemicellulose hydrolysis. The modeling process resulted in an analytically derived reactor equation, including mass‐transfer effects, which was found to be useful in process desing and reactor optimization. The modedl was verified by experimental data obtained from hemicellulose hydro